Judy's Cards

A window is an opening in an otherwise solid, opaque surface through which light and sometimes air can pass. For example, a window in the wall of a house, or a window in a scientific measurement device that permits reading of certain wavelengths. Window is also used metaphorically to refer to a time period during which something can occur and outside of which the thing cannot occur, as in a window of opportunity to launch a rocket to the moon on the most efficient trajectory. (from Wikipedia)